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Investigation of a turbulent spot and a tripped turbulent boundary layer flow using time-resolved tomographic PIV

Schröder, Andreas und Geisler, Reinhard und Elsinga, Gerrit E. und Scarano, Fulvio und Dierksheide, Uwe (2006) Investigation of a turbulent spot and a tripped turbulent boundary layer flow using time-resolved tomographic PIV. Experiments in Fluids, Vol.: 44 (2), Seiten 305-316. Springer Verlag Berlin/Heidelberg. DOI: 10.1007/s00348-007-0403-2. ISSN 0723-4864 (PRINT) 1432-114 (ONLINE).

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Kurzfassung

In this feasibility study the tomographic PIV technique has been applied to time resolved PIV recordings for the study of the growth of a turbulent spot in a laminar flat plate boundary layer and to visualize the topology of coherent flow structures within a tripped turbulent flat plate boundary layer flow. The experiments are performed around (Re<sub>x</sub> )<sup>½</sup> ≈ 450 in a low speed wind-tunnel using four high speed CMOS cameras operating up to 5 kHz. The volume illumination required a multiple-reflection system able to intensify light intensity within the measurement volume. This aspect is deemed essential when a high-speed tomographic PIV system is applied in air flows. The particle image recordings are used for a three dimensional tomographic reconstruction of the light intensity distribution within the illuminated volume. Each pair of reconstructed three-dimensional light distributions is analyzed by 3D spatial cross-correlation using iterative multi-grid schemes with volume-deformation, yielding a correlated time sequence of three-dimensional instantaneous velocity vector volumes. The coherent structures organization is analyzed by 3D-vorticity and -swirling-strength iso-surfaces visualization. In both flow types streaks and hairpin-like or arch vortical structures are most prominent. The data giving insight into the role of these structures for the spatio-temporal arrangement of the wall normal flow exchange mechanisms, especially of the instantaneous Reynolds stress events Q2 and Q4. A description of different self-sustainable flow organizations based on modifications of the hairpin-vortex- and streak- models is given. Two preliminary results are essential: Self-sustainability of a coherent vortical structure depends on the possibility to entrain high momentum fluid, initially Q4. And, stream-wise swirl at the near-wall region of arch or hairpin-like vortices has been observed to be seldom.

Dokumentart:Zeitschriftenbeitrag
Zusätzliche Informationen:published online: 13. October 2007
Titel:Investigation of a turbulent spot and a tripped turbulent boundary layer flow using time-resolved tomographic PIV
Autoren:
AutorenInstitution oder E-Mail-Adresse der Autoren
Schröder, AndreasNICHT SPEZIFIZIERT
Geisler, ReinhardNICHT SPEZIFIZIERT
Elsinga, Gerrit E.Delft University of Technology, Department of Aerospace Engineering, Delft, The Netherlands
Scarano, FulvioDelft University of Technology, Department of Aerospace Engineering, Delft, The Netherlands
Dierksheide, UweLaVision, Göttingen
Datum:2 Oktober 2006
Erschienen in:Experiments in Fluids
Referierte Publikation:Ja
In ISI Web of Science:Ja
Band:Vol.: 44
DOI :10.1007/s00348-007-0403-2
Seitenbereich:Seiten 305-316
Verlag:Springer Verlag Berlin/Heidelberg
Name der Reihe:Journal
ISSN:0723-4864 (PRINT) 1432-114 (ONLINE)
Status:veröffentlicht
Stichwörter:turbulent boundary layer, high speed tomographic PIV, 4-D PIV
HGF - Forschungsbereich:Verkehr und Weltraum (alt)
HGF - Programm:Luftfahrt
HGF - Programmthema:Starrflügler
DLR - Schwerpunkt:Luftfahrt
DLR - Forschungsgebiet:L AR - Starrflüglerforschung
DLR - Teilgebiet (Projekt, Vorhaben):L - Flugphysik
Standort: Göttingen
Institute & Einrichtungen:Institut für Aerodynamik und Strömungstechnik > Experimentelle Verfahren
Hinterlegt von: Ilka Micknaus
Hinterlegt am:27 Jul 2007
Letzte Änderung:14 Jan 2010 23:29

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